[Milsurplus] GRA-53 / GRA-54

[Bruce Gentry]

I worked on the GRA-53 in the US Air Force in 1970-71. Because of the 
markings and manual, I knew there was a mobile version as well, but did 
not see one until I got one of my own years later. The main repair 
problems were caused by the tantalum condensors in the transceiver 
shorting out, usually causing an obvious or total failure and easy to 
find and repair. They ran HOT, and in southeast Asia that was 
exascerbated by the climate. In an air conditioned room it was 
managable. The worst problem with them and their cousins the ARC and 
GRC-27 was getting them to work to book and inspection specifications. 
They would easily  produce 90% of output power and break squelch at 3.2 
microvolts day in day out for months, but getting them to 100% of output 
and under 3 microvolts sensitivity was for all practical purposes 
impossible. Massive tube replacements and re-alignment (DAYS of 
tweaking,  praying, and sometimes cursing) would get them to produce 
100.5% of rated power and break squelch at 2.999 microvolts for a day or 
so, pass inspection, and quell the lifers. They WILL work on the 220 Mc 
band if the trimmers on the wideband tuners are tweaked. It is also 
possible to use them as a transverter for AM or FM.   I have tried to 
entice some locals to get something going on the  220 band, but no one 
seems to care around here.  I KNOW! it's really 222-225, but like to say 
220 to let "them" know  the loss of the 2 megs is remembered, the new 
uses are a failure, and they  should be returned.

        Bruce Gentry, KA2IVY


On 9/1/16 11:05 AM, antqradio at sbcglobal.net wrote:
> The above are similar to the VRC-24, TRC-68 and URC-9 UHF 
> multi-channel transceivers of the late 1950's and early 1960's.  The 
> VRC-24 and the TRC-68 share a common manual but the URC-9 is in a 
> class of it's own although it is the same RT unit with a slightly 
> different die-cast front panel, is in grey instead of OD and of 
> course, Navy.
>
> I am curious about the heritage of the design. If one goes by RT 
> numbers, then it seems that the sequence is:
>
> VRC-24 with RT-323
> TRC-68 with RT-441
> URC-9 with RT-581
>
> But I have no idea where the GRA-53 and GRA-54 fit into the lineage. 
>  When I was in the Air Force and stationed at Mactan, AB, Philippians 
> in the late 1960's, I worked on TRC-68's, GRA-53's and GRA-54's.   
> Long after I was discharged I learned about the VRC-24 and URC-9 versions.
>
> If anyone is lucky enough to have examples of the GRA's in their 
> collection, could you please send photos of the nomenclature tags on 
> the RT unit, power supply and case?  Stories about working on these 
> beasts are also welcome.  Anyone have the extension cable that allows 
> operation of the RT unit outside of the case?
>
> Thanks in advance,
> Jim
>
>
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